Spinal Surgery Anesthesia Flashcards

1
Q

What is scoliosis?

A

Lateral rotation of the spine > 10° with vertebral rotation.

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2
Q

What are the effects of thoracic spine scoliosis?

A
  • ↓ Chest wall compliance
  • Restrictive lung disease
  • ↓ exercise tolerance

Get PFTs!

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3
Q

What EKG/cardiac findings might one suspect to find on a scoliosis patient? (Select all that apply)

a. RVH
b. RAE
c. LVH
d. Bi-atrial enlargement

A

a & b

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4
Q

The increased pulmonary vascular resistance of chronic, significant scoliosis can lead to ___ _______.

A

cor pulmonale

Enlarged RV due to lung disease.

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5
Q

What muscles would you expect to be effected from a C5 injury?

A
  • Partial diaphragmatic paralaysis
  • Deltoids
  • Biceps
  • Brachialis
  • Brachio-radialis
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6
Q

What are the hemodynamic consequences of injuries T5 and higher?

A

Physiologic Sympathectomy
- ↓BP
- ↓HR

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7
Q

Autonomic Hyperreflexia is most often seen with cord transection above the ____ level.

A

T5/T6

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8
Q

What s/s are seen with autonomic hyperreflexia?

A
  • Severe, transient HTN
  • Bradycardia
  • Dysrhythmias
  • Cutaneous dilation and constriction
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9
Q

In autonomic hyperreflexia, cutaneous vasodilation is seen _____ the site of injury, whilst cutaneous vasoconstriction is seen ____ the site of injury.

A

above ; below

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10
Q

What is the basic pathophysiology of Autonomic Dysreflexia?

A
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11
Q

What are the most common causes of Autonomic Dysreflexia?

A
  1. Distended bladder/bowel
  2. Noxious stimuli (think surgical pain)
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12
Q

What is the treatment for Autonomic Dysreflexia?

A
  1. Removal of stimulus
  2. Deepen anesthetic
  3. Direct-acting Vasodilators
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13
Q

Injury to C3-C5 results in….

A

Diaphragmatic respiratory failure

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14
Q

Is respiratory function affected by injury to C5-C7?

A

Yes; impairment of abdominal and intercostal respiratory support

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15
Q

Why is there an increased risk of pulmonary infection with cervical spine injuries?

A
  • Inability to cough/ clear secretions
  • Atelectasis
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16
Q

What is poikilothermia?

A

Inability to maintain constant core temp

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17
Q

What is the pathophysiology of poikilothermia?

A
  • SNS disruption
  • Temperature sensation disruption
  • Inability to vasoconstrict below spinal cord injury
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18
Q

Spinal deformities are associated with _______ respiratory patterns, often necessitating PFT’s and an ABG.

A

Restrictive

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19
Q

Flaccidity in which two muscles would indicated possible cervical spine fracture?

A
  • Deltoids
  • Biceps
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20
Q

What is the greatest risk with a total sitting position?

A

VAE (Venous Air Embolism)

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21
Q

An anterior approach for a thoracic spine procedure requires what position and equipment?

A
  • Lateral position with bag
  • Double Lumen ETT or bronchial blocker

May have to drop lung for access.

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22
Q

A posterior approach for a thoracic spine procedure requires what position and equipment?

A
  • Prone with arms tucked or 90° abduction
  • Single lumen ETT.
23
Q

What are the three causes of postoperative vision loss secondary to prone positioning?

A
  • Ischemic Optic Neuropathy (ION)
  • Retinal vessel occlusion
  • Cortical brain ischemia
24
Q

T/F. Ischemic optic neuropathy occurrence requires direct pressure placed on the eyes?

A

False. Can occur without direct pressure.

*Occurs due to ↓ blood flow or O₂ delivery.

25
What are risk factors for ION?
- Male - Obesity - Wilson Frame Use - > 6 hour surgery - ↓ colloid usage - Blood loss > 1000 mL
26
What is the typical onset of ION?
24 - 48 hours
27
What are the symptoms of ION?
Bilateral - Painless vision loss - Non-reactive pupils - No light perception
28
What are the treatments for ION?
- Acetazolamide - Corticosteroids - Hyperbaric O₂
29
What time of frame pictured below?
Wilson Frame
30
What are the respiratory effects of prone positioning?
↓ FRC ↓ compliance *Due to ↑ intrabdominal pressures → ↑ intrathoracic pressures*.
31
Does venous return increase or decrease in prone positioning?
decrease
32
Which of the following positioning devices is the most stable?
Mayfield Tongs
33
What cardiac consequences are there to prone positioning? Why?
- ↓ preload - ↓ CO - ↓ BP *Due to pooling of blood in extremities and compression of abdominal contents and muscles*.
34
What neurological consequences occur due to prone positioning?
↓ cerebral venous drainage and ↓ CBF
35
What risk factors are there for increased blood loss during spinal surgery?
- Number of vertebrae - > 50 yo - Obesity - Tumor surgery - ↑ intrabdominal pressure - Transpedicular osteotomy
36
When is autologous blood donation contraindicated in spinal surgery?
- Significant cardiac disease - Infection
37
What is the push dose of TXA?
- 10 mg/kg IV
38
What is the infusion dose of TXA?
2 mg/kg/hr
39
What is the push dose of aminocaproic acid? Infusion dose?
Push dose: 100 mg/kg IV Infusion: 10 - 15 mg/kg/hr
40
Somatosensory Evoked Potentials (SSEPs) are associated with what spinal column and sensations?
Dorsal column pathways - Proprioception - Vibration
41
Motor Evoked Potentials (MEPs) are associated with what spinal column and sensations?
Anterior/ Motor Column
42
During spinal surgery, electromyogram (EMG) is used to monitor for what during pedicle screw placement and nerve decompression?
Monitor for **nerve root injury**.
43
What is an SSEP?
Impulse from a peripheral nerve that is measured centrally.
44
What are Motor Evoked Potentials (MEPs)?
Impulse triggered in the brain (centrally) and monitored in specific muscle groups.
45
What are possible adverse effects associated with MEPs?
- Cognitive defects - Seizures - Intraoperative awareness - Scalp burns - Cardiac arrythmias - Bite injuries (bite block necessary)
46
In what patients should MEPs be avoided?
- Patients w/ active seizures - Patients w/ vascular clips in brain - Patients w/ cochlear implants
47
Differentiate amplitude and latency in regards to neurophysiologic monitoring.
Amplitude: signal strength Latency: time for signal to travel through spinal cord.
48
What physiologic factors commonly can affect amplitude and latency of neurophysiologic monitoring?
- Hypothermia - Hypotension - Hypocarbia - Anemia - **VAAs**
49
How do VAAs affect neurophysiologic agents?
Dose dependent - ↓ amplitude - ↑ latency
50
Out of the following drugs, which affects our MEPs the most? - Opioids - Midazolam - Ketamine - Propofol
Propofol **depresses MEPs**. *The others have little effect on MEPs*.
51
How much does muscle relaxant requirement increase when using MEPs?
Trick question. **No muscle relaxants after intubation.**
52
What type of nerve block might be used for spinal surgery?
Erector Spinae block
53
During what surgery is venous air embolism at its greatest risk of happening?
Laminectomies - Large amount of exposed bone - Surgical site above the heart
54
What are some s/s of VAE?
- Unexplained ↓BP - ↑ EtN₂ - ↓ EtCO₂